JP4544747B2 - Method and apparatus for simultaneous determination of eye surface topometry and biometrics - Google Patents

Abstract

An apparatus (10') for detecting the surface topography of a cornea (24) of an eye (22) by dynamic or static projection of a pattern onto the surface of the cornea and detection of the pattern reflected by the cornea, providing preferably simultaneous detection of at least one optical property of a layer disposed beneath the cornea.

Description

[0001]
(Technical field)
The present invention provides eye surface topometry using means for dynamic or static projection of a pattern onto the corneal surface and means for detecting a pattern reflected or projected by the cornea. The present invention relates to a method and apparatus for detection. The term “layer” shall be construed hereinafter in tomographic terms and is not limited to thin boundary layers between zones of different refractive index.
[0002]
(Background technology)
The pattern is projected statically (eg DE 43 25 494 A1 or US 5,684,562) or dynamically (eg DE 43 22 620 A1) and reflected from the cornea A wide variety of methods and apparatus are known for detecting the surface morphology of the cornea where a pattern to be played or projected is detected. Such a method is usually called video corneal curvature measurement or ring projection according to placido and has proven its value in general practice. They allow measurements on the surface of the cornea within a few milliseconds (in most cases using more than 8000 measurement points).
[0003]
The morphology of the corneal surface is derived from the location of the projection points and the relative relationship of those points that form the ring pattern. The reflected pattern is usually recorded by a CCD array, for example with a CCD array such as a CCD array of a video camera, and is usually arranged coaxially and concentrically at the end of a so-called placido cone. . However, this setup determines a central corneal region having a diameter of about 0.5 mm in relation to the refractive power of the eye, and it is in particular the central optical zone of the cornea that forms the passing point of the visual axis, The result is that it cannot be detected during the measurement. The so-called Styles-Crawford effect results in a central corneal zone that is free from any pattern playing a special role with respect to the surrounding corneal region in the projected tissue of the eye during projection of the placido pattern.
[0004]
Furthermore, video corneal curvature measurement, also shown as video morphology, cannot provide information on the back of the cornea and the lower section of the refractive tissue of the eye, particularly the front and back of the lens. Boundary surface geometry, anterior chamber depth of the eye, boundary surface properties, and lens morphology, density distribution within the lens and scattering body array, and (defined by the distance between the lens and the retina The depth of the posterior chamber of the eye can improve the accuracy of refractive measurements on the cornea, and implant surgery with a lens for computer-aided detection and analysis of the refractive system of the patient's entire eye optical properties. It is a precondition for intervention.
However, some of these devices (DE 43 25 494 A1 or US Pat. No. 5,684,562) align the projected pattern to the eye or position the eye in the projected pattern. Provides a means for matching. These alignment means may provide certain information about the eye under the cornea by processing the light reflected by the inner structure of the eye. Such information is particularly ambiguous along the optical axis of the eye.
As an alternative, US Pat. No. 5,491,524 proposes to use optical coherent morphology (OCT) to prepare for surface morphology results. However, this method cannot provide information about the geometric location where the measurement occurs. In particular, the natural movement of the eye cannot be calibrated.
[0005]
With this in mind, the present invention provides, in a simple and rapid manner, the complete substantial surface morphology of the cornea and of at least one optical property of the eye layer placed under the cornea with relatively high accuracy. Both are based on the object of providing a method and apparatus that allow detection.
[0006]
(Disclosure of the Invention)
This object is provided for detecting at least one optical property of a layer placed under the cornea of the eye comprising coherent tomographic means. The object is that a method of the kind described above in which at least one optical property of the layer of the eye placed under the cornea is detected in parallel to the cornea surface tomography detection process via coherence tomography. Is also achieved.
[0007]
Such a setup and such a method allow the measurements required in one process to be performed. This is very comfortable for those who take such measurements. In addition, this setup allows the detection of the optical properties of the layers under the cornea together with the required local calibration, since such local calibration is made possible by detection of the surface morphology of the cornea. Also ensure that it occurs. In this way, it is no longer necessary for a person to stare closely at the focused light while measuring the optical properties of a layer placed under the cornea that is not physiologically possible. Rather, smaller deviations can be measured accordingly by the detected surface morphology. In this way, the device and method according to the invention make it possible to initially determine the optical properties of the entire eye with sufficiently high local accuracy.
[0008]
For example, an apparatus according to the invention comprises at least one laser light source, a detector for detecting a laser beam produced by the laser light source, and splitting the beam and deflecting at least part of the beam into the eye. Means for deflecting the detector part of the laser beam reflected in the eye.
[0009]
Such a device compares the surface morphology with the overall refraction of the eye and thus makes it possible to detect the effects and data of optical media placed deeper in the eye. In addition, an analysis of the scattered image can be obtained from the tissue portion of the eye. In particular, the central portion that cannot be detected in terms of mechanical contour can be detected topographically and topographically using the device.
[0010]
Thus, the laser beam is produced by at least one laser source in a manner according to the invention and can be split and deflected in such a way that at least part of the beam is guided into the eye and reflected by the eye A portion of the laser beam is directed to the detector and detected by the detector.
[0011]
Depending on the respective problem to be solved, the method can be carried out in such a way that the contour of the wavefront of the laser beam aimed at the eye is compared with the contour of the wavefront reflected by the eye. As an alternative or in addition, the method can also be performed in such a way that a continuous period of the laser beam emitted into the eye is required.
[0012]
The measurement will be accurate and easy to perform especially when the placido topometer is used to project a pattern onto the surface of the cornea. In this process, the laser beam can be guided in its path toward and back through the beam of a placidotopometer to detect the optical properties of the layer placed under the cornea. For this purpose, suitable deflection means such as tilting mirrors or deflecting prisms are used.
[0013]
In order to determine the optical properties of the layer placed under the cornea, a known wavefront of the laser source in the zone of the known beam contour or pupil opening is introduced and applied over the cornea and the lower section of the eye. Can be directed to. It is possible to detect the optical properties by determining the contour form of the wavefront reflected by the eye and comparing it with the wavefront sent into the eye. The Hartmann-Shack detector is particularly suitable for this purpose. Such a device would produce a very accurate picture of the optical properties of the eye layer placed under the cornea.
[0014]
Alternatively, or dramatically, it is possible to provide optical coherent mechanistic morphology (OCT) to determine the optical properties of a layer placed under the cornea. Such coherent morphology proves its value, reliably supplies topographs from the entire eye, and also includes information on the layer thickness of the individual parts of the eye that are related in terms of refraction (biometrics). In particular, the method and apparatus according to the present invention can each be corrected by continuous simultaneous detection of the corneal surface morphology. These surface morphology based mathematical calculations can be used to compensate for corneal motion during data acquisition, and thus also used to compensate for motion errors for OCT measurements. it can.
[0015]
Corneal morphology within the central corneal region is coaxial with the optical axis extending through the pupil and retina, in which the short interferometry system, in particular the laser measurement system, is projected in the cornea in the placido ring free region in the center of the cornea In particular, it can be determined to be aimed at the cornea and the lower section of the eye. In addition, OCT offers advantages for measuring tissue and other optical properties of various layers inside the eye. For example, these data can be used to measure and analyze the corneal wound healing process in stromal tissue after refractive surgery.
[0016]
Because the time required to capture OCT information is substantially longer than the morphological acquisition time-instead of just one morphology-multiple morphologies are due to accidental eye movements In order to detect and compensate for human movement artifacts, it must be done during the OCT acquisition.
[0017]
The unresolved problem of positioning the cornea and the measuring device can be solved as follows. That is, not only the wavefront detector but also the OCT can be correlated to the topographer's reference point (eg, the patient's line of sight). This is accomplished by using the same fixed light and wavefront detection or OCT for morphology, allowing the starting point of data analysis to be calculated in x / y coordinates.
[0018]
OCT also provides information on the morphology of the optical components associated with the eye (cornea, lens, vitreous humor) by acquiring special information in the layers obtained by appropriate adjustment of the z-axis. In this way, morphology, optics, and density meter data from the inside of the cornea and lens can be obtained. As a diagnostic and topographic tool for refractive surgery, only OCT can provide such data related to diagnosis and therapy. The form information can also be obtained in combination with wavelength selection based on OCT alone or data acquisition based on x-axis variation.
[0019]
OCT measurements at multiple points (in the middle and slightly in the middle) allow the lens to move in its original location. Such measurements depend on splitting the OCT (either statically using the prism or dynamically using the scanning device) and subsequent evaluation of the difference in execution time of each beam. Can be achieved. Beam splitting in one of the described methods allows triangulation measurement of lens position, essential morphometric information.
[0020]
Apart from the static projection of the placido ring pattern onto the cornea (fissure film), the dynamic projection of one or more light sources is used not only for OCT scan information but also for the morphology of the cornea surface Obtainable. Thus, the Purcine image (1 = surface cornea, 2 = rear corneal surface, 3 = front lens surface, 4 = rear lens surface, 5 = retina) is used to measure the optically related surface. it can.
[0021]
Further objects and advantages of the present invention are provided by the following description in combination with the drawings of two embodiments of the present invention, which are selected merely as examples and should not be construed as limiting in any way.
[0022]
The apparatus shown in FIGS. 1, 3 and 4 and generally designated by reference numerals 10 and 10 ′ is a placido topometer with two components: a cone 12 with a random opening angle. , A CCD array 14 and an annular lamp 16 for illuminating the outer wall of the cone 18 as well as a wavefront analyzer (FIG. 1) or optical coherence tomograph (FIGS. 3 and 4). A number of annularly extending apertures 20 are referenced to a limited number for reasons of clarity of illustration so that the light produced by the conical lamp 16 can pass through it, so that the pattern is the eye 22, That is, it is introduced into the outer wall of the cone 18 of the placido cone 12 which is projected in a known manner on the cornea 24 to be examined more specifically. The ring-shaped opening 20 is related to the slot in the simplest case among the cases, so that the projected ring is monochromatic. It is also possible to introduce various nets or grids so that the projected ring is pattern coded and allows a simpler assignment of the ring's geometry to the origin. It is also possible to introduce different color filters into the individual openings in order to encode the ring thus projected in color.
[0023]
During operation of the device, the light-emitting cone is reflected by a reflective surface, such as the surface of the cornea 24. The reflected image is reproduced through the lens 26 of the CCD array 14 of the video camera. An image of the surface with the reflection image of the conical ring is then provided to an evaluator device, eg, a PC or workstation, for further processing.
[0024]
The placido topometer, which in the illustrated example is a placido ring topometer, allows measurement of the surface of the cornea 24 within a few milliseconds by recording more than 8,000 measurement points. However, this has the disadvantage that it does not supply information from a deeper section of the eye. However, this information is for purposes that the placido topometer is provided in accordance with the present invention in conjunction with a beam contour or wavefront analyzer (FIGS. 1 and 2), or optical coherence tomography (FIGS. 3 and 4), Can be provided by wavefront analysis (FIGS. 1 and 2) or coherent morphology (FIGS. 3 and 4).
[0025]
The beam contour or wavefront analyzer consists of a laser source 28 that emits a beam profile in a known manner, for example, a Gaussian beam profile. This laser source can emit infrared or other light of known optical path length. The wavefront 32 is read through the beam splitter 30 by the respective detector field, for example by the Hartmann-Shack sensor 34. The contour of the wavefront 32 is determined from the acquired data. The portion of the laser beam that is not projected is directed to the eye 22. The diameter of the laser beam depends on the diameter of the pupil and can optionally be expanded or reduced by a lens system (telescope 28 ') depending on the type of laser source. The wavefront reflected by the cornea 36 or the rear column of the eye 22 is deflected to the detector 34 by a partially transparent mirror (beam splitter 30). The difference between the two wavefronts shown below each other in the upper right part of FIG. 2 next to the detector 34 to show its different form, namely the input wave 32 and the wave 38 reflected in the eye, is Allows to draw conclusions of local differences in execution time. Thereby, a local difference in refraction can be obtained. In connection with surface morphology, not only can the surface of the cornea be described in terms of the form and curvature of local coding, but the influence of deep refractive media on the overall refractive power can also be determined.
[0026]
To combine the two measurement methods, the aperture 40 is introduced at any position in the beam path of the placido topometer (FIG. 1) through which the wavefront analyzer laser beam can be directed. A small deflecting mirror 42 is mounted inside the placido cone that will redirect the wavefront analyzer laser beam in parallel or at a known angle to the axis of the eye relative to the CCD array. The deflection mirror 42 can be attached to the center as well as outside the center of the placido cone. It is also possible to consider other beam guiding objects (eg prisms) instead of deflecting mirrors. The additional deviation mirror 44 is provided in a device such as that shown in FIG. 1 and, of course, the mirror can be omitted depending on the arrangement of the laser light sources 28.
[0027]
Furthermore, if the laser light emitted by the laser source 28 cannot be used as so-called patient fixed light, the device allows an eye to be examined during the examination in that it focuses on the light 46 that it focuses. It includes an additional focused light 46 that helps the patient to be examined to be as stable as possible, and an evaluator 48 coupled to the detector 34. A central evaluation controller is provided in the form of a PC that evaluates data received from the CCD array 14 as well as from the detector 34 and simultaneously controls the apparatus according to the problem to be solved. In this way, the acquired data can be used, for example, to determine the overall optical behavior of the eye or a significant part of the eye, such as the eye lens 50, for example. From information about the radius of curvature of the corneal surface and the overall refraction of the eye, for example, it is possible to calculate with high accuracy lens data in an artificial eye for a patient suffering from cataract.
[0028]
In this process, the described measurements can be performed either in a recording sequence or continuously. Furthermore, the desired combination of individual measurements is possible within a definable time interval. Both measurement processes can be adjusted through respective automatic control processes that control not only the selection of essential information but also the recording sequence according to the problem to be solved. For example, according to the problem to be solved selected by the operator through the control menu, the measurement to be performed will be automatically selected and then performed in the sequence most appropriate for each application. The result of the measurement is in the form of a color-coded card for the artificial lens radius or evaluation value, or as a computer file for additional use, such as during automatic production of the artificial lens, for example on the screen, Or it can be output by a printer.
[0029]
The combination of methods leads to a quantitative description of eyes that are qualitatively new and have not been achieved in the past in terms of diagnosis and treatment. Combined with a method (see DE 195 163 091 A1) for fast calculation of absolute coordinates and ray tracing in free space as developed by the applicant, not only optical boundary services, The probability of determining optical quality in a meteorologically objective way is also specified for the first time. With the help of a ray tracing program, it is possible to quantify the overall refraction system in vivo and in situ based on data as obtained by the device. Biometric data allows analysis of individual functional parameters and the expected calculation of visual sensitivity, contrast sensitivity. At the same time, the results of the planned surgical intervention (ie, intrastromal ring, phatic IOL, PRK, LASIK) can be calculated and thus predicted in-scope--within the "expert" software program.
[0030]
As a result of the combination of the two programs, automated laser surgery includes comprehensive topological / morphological corneas that could not be achieved in the past, from the outermost peripheral cornea to the range of the visual axis through the cornea. A figure is provided. On the other hand, this leads to the opportunity to use the complete data record (possibly along with its connection to the ray tracing program) to introduce an optimal removal pattern to the front of the cornea individually by the light removal laser. The data acquired in this way separates the ablation process from the dexterity of the surgeon's hand and provides it as a data record for automated ablation of tissue with the laser itself. As a result of its completeness across the cross-section, it can be used according to a method known under the name “auxiliary or guided morphology”.
[0031]
Corneal morphology and wavefront analysis in the eye lead to new possibilities in the calculation of individually manufactured intraocular lenses. For the first time, they allow a refractive state that is visually optimized for individual patients for medical care with contact lenses, not just with intraocular lenses. In this way, it is possible to greatly change the scope of previous medical care with contact lenses and with intraocular lens implants. Finally, the system is generally based on an approach that leads to cost savings for health systems where additional correction aids such as eyeglasses that are still needed in more than 70% of cases are avoided.
[0032]
FIGS. 3 and 4 show an apparatus 10 ′ that substantially comprises a placido topometer, as well as an optical coherence tomograph, as well as a placido cone 12, a conical lamp 16, and a CCD array 14. The aperture 40 'is introduced into the placido cone 12 that can guide the coherence tomography laser beam. A miniature deflecting mirror 42 is mounted inside the placido cone 12, which mirror will redirect the coherence tomography laser beam in parallel or at a known angle to the axis of the eye to the CCD array. The deflecting mirror 42 'can be attached not only to the outside of the center of the placido cone but also to the center. Instead of a deflecting mirror, other beam guiding objects (eg prisms) can be considered.
[0033]
An coherent tomography machine (OCT) essentially consists essentially of a laser light source 28. That is, a so-called SLD laser diode detects a laser light source, for example, a prism splitter 52 that divides a laser beam onto two reference mirrors 54 and 56, and not only the luminance operation of incident laser light but also the operating time and phase shift. It can be used as a laser light source such as a photodetector 34 '. As shown in FIG. 3, an additional deflecting mirror 58 (FIG. 3) or 58 ′ (FIG. 4) is further provided, which can be arranged to pivot about two axes, so that it It can serve as an “x / y scanner”. In addition, focusing lens systems (lenses 60 and 62) for beam focusing are provided for boundary surface detection purposes, where the beam diameter is as small as possible at the laser beam passage point 40 'through the placido cone 12, It is arranged that only a very small loss of information occurs during the placido measurement. A dual beam reference mirror is further provided in the apparatus according to FIG. 3, which provides a reference plane for the corneal geometry.
[0034]
The focal point where the laser beam is focused in the eye after its last deflecting mirror 42 'defines the measurement point, ie the measurement plane of the coherence tomograph. For example, to detect individual interfaces on the eye (front and back surfaces of the cornea, front and back surfaces of the lens, base of the eye), the focal point is moved along the optical axis through the eye. There must be. An example is shown in FIGS. 3 and 4 by a rotating or oscillating double mirror optical path length modulator 66 inserted in the beam path between the prism splitter 52 and the first reference mirror 54, as shown in FIGS. Given in the embodiment. As a result of moving the modulator, the focal point of the laser beam is directed from the anterior surface of the cornea to the base of the eye. The signal maximum occurs in the detector 34 'at each optical interface. As a result of the optical path length modulator angle encoding, each reflection point can be assigned to a linear reference. That is, the person obtains distance information in the eye along the optical axis between each optical boundary surface. These data can be used, for example, for comprehensive biometrics of the eye.
[0035]
If the deflection mirror 58 is held pivotably about two axes, as shown in FIG. 3, surface scanning can be performed in any desired plane. For this purpose, the optical path length modulator is paused according to the desired target surface and the incoming laser beam is directed by the deflecting mirror 58 to different points in the plane. In this way, it is possible to measure with high accuracy the central part of the cornea which cannot be measured with the placido topometer, for example—as already mentioned above—as a result of its design. In addition, the defined advance of the measurement surface (rotation of the optical path length modulator) then provides three-dimensional information about the volume measured as a whole and changes in the structure of the optical system (scattering, absorption, reflection etc.) It is possible to measure a desired number of closely following planes that can provide additional information about. Such a diagnostic statement was not possible before.
[0036]
By using the limited x / y positions provided by mirror 58 (eg, 3 or 4 positions), the lens eccentricity or tilt is determined when the surface morphology is combined with OCT measurement data. It can be so.
[0037]
As already mentioned in connection with FIGS. 1 and 2, measurements using the placido topometer and coherence tomography can be performed simultaneously or sequentially. As also mentioned above, the combination of placido optometry and coherent morphology leads to a quantitative description of the eye, qualitatively new and not achievable in the past, in terms of diagnosis and treatment. Quantify the overall refraction system after acquisition of data using the device according to the present invention, including shadowing the media during the wound healing process and wound formation with the help of a ray tracing program It is possible in vivo and as such. For example, the apparatus and method according to the present invention can be used to obtain layer-by-layer information on scattering states, for which there is an urgent need not only for diagnosis but also for forensic medicine. For example, after corneal surgery it is possible to determine objective criteria for the treatment of haze formation and wounding without resorting to physically simplifying forward light scatter.
[0038]
A further important application is the treatment and risk stratification of cataracts that would later affect up to 100% of the population due to an increasing shift in the artificial age structure. The present invention allows an objective decision regarding clouding of the cornea. Our knowledge of not only the anterior and posterior surfaces of the lens and the depth of the anterior chamber of the eye, but also the other properties of the entire optical refractive system, including the anterior and posterior surfaces of the cornea, is an objective predictable vision Allow accuracy to be determined from there.
[0039]
An objective grading of the anterior chamber and lens can be created from the interaction between calculated visual acuity and clinically observed acuity. Even obtaining objective criteria for grading the stage of clouding phenomenon in vivo and in vitro alone will have widespread consequences for the diagnosis and therapy of very specific eye diseases.
[0040]
The invention also allows qualitatively definitive improvements in the field of biometrics. Conventional biometric methods based on ultrasound performed prior to cataract surgery, and the insertion of artificial lenses, ultimately work with simplification that does not allow for optimal visual results. Since the posterior surface of the cornea has not been qualitatively detectable to date, it is not possible in part to determine any curvature of the lens, and as a minimum it can be decentered and displaced and consequently inserted The lens was calculated incorrectly. The socio-economic consequences of the procedure to date are enormous. So to date, the theoretically possible maximum rate of visual acuity has not been achieved in about 80% of all cases of lens insertion after cataract surgery, resulting in cost-intensive correction with glasses. It was said. If the incorrect calculation between RA / LA exceeds 3 diopters, an additional problem of anisotropy may arise. The present invention is the first time that data records are recorded in a particularly simple way using surface topometry and coherent morphology and / or wavefront analysis to accurately calculate the optimal implant for every individual case. Deal by making decisions.
[0041]
Within the scope of the present invention, it is possible to provide a number of modifications, for example developments relating to the type and sequence of the placido topometer. In this way, for example, the placido pattern is not generated statically on the cornea with the help of the placido cone, but instead the pattern can be generated dynamically, for example by rotating the LED. It is likewise possible for laser light directed for wavefront analysis or coherent morphology to be projected statically or dynamically. A related aspect of the invention is in any case where a topometer and wavefront analyzer or coherence tomograph are combined in one device.
[Brief description of the drawings]
FIG. 1 shows the main arrangement of a device with a placido topometer and a wavefront analyzer.
FIG. 2 is a diagram showing main operation modes of the wavefront analyzer.
FIG. 3 shows the arrangement of a device with a placido topometer and an optical coherence tomograph with an optical coherence tomograph set up to obtain tomography from the front section of the eye.
FIG. 4 shows the apparatus according to FIG. 3, but the coherence tomograph shows an apparatus with a coherence tomograph set up to perform a scan in the middle section of the eye and the posterior section of the eye. Figure.

Claims (19)

The cornea of the eye (22) with means (12, 16) for dynamic or static projection of the pattern onto the surface of the cornea and means (14) for detecting the pattern reflected by the cornea An apparatus (10, 10 ') for detecting the surface morphology of (24), whereby means are provided for the detection of at least one optical property of a layer placed under the cornea, said detection The means comprises coherent morphological means;
At least one laser light source (28), a detector (34, 34 ') for detecting the laser beam produced by the laser light source, and splitting the laser beam, deflecting at least a portion of the laser beam into the eye; Means (30, 52) are provided for deflecting the portion of the laser beam reflected from the eye onto the detector;
A detector (34) is arranged to perform optical coherent morphology and, in addition to the detector , is a prism splitter (52), an optical path length modulator, which is an additional means for performing optical coherent morphology (66) and two reference mirrors (54, 56).   Comprising means for projecting a pattern onto the surface of the cornea, comprising a placido topometer (12, 16), and means for deflecting the laser beam in the course of reaching the eye and returning from the eye again The device (10) according to claim 1, characterized in that it is arranged to be guided through the beam path of a placido topometer.   The apparatus according to claim 1 or 2, wherein the means for deflecting the laser beam comprises a deflecting mirror (42) or a deflecting prism arranged in the placido topometer. The detector for detecting the laser beam is a detector (34), which is a Hartmann-Shack detector , enabling the determination of the contour shape of the wavefront of the detected laser beam. The device (10) according to any one of claims 1 to 3.   Device (10 ') according to any one of the preceding claims, characterized in that the optical path length modulator is a rotating or pivoting double mirror optical path length modulator (66).   Device according to any one of the preceding claims, characterized in that means (58) are provided for deflecting the laser beam directed into the eye to various points in the plane.   Device according to claim 6, characterized in that the means for deflecting the laser beam directed into the eye to various points in the plane comprise at least one pivotable mirror (58). A method for detecting the surface morphology of the eye cornea by dynamic or static projection of the pattern onto the surface of the cornea and for detecting a pattern reflected by the cornea, thereby At least one optical property of the underlying layer is also detected, said detection of said optical property of the underlying layer being performed by coherent morphology,
A laser beam is generated by at least one laser light source or a beam for detecting optical properties of a layer placed under the cornea and deflected so that at least a portion of the beam is guided into the eye, The portion of the laser beam reflected by is directed to the detector and detected by the detector,
A method characterized in that within the scale of the penetration depth of the laser beam, information on the scattering value is determined by optical coherent morphology (OCT) within the layer thickness of the tissue (cornea, lens, retina).   9. A pattern comprising a pattern projected onto the surface of the cornea by a placido topometer, wherein the laser beam is guided through the beam path of the placido topometer on its way to the eye and back again. The method described in 1.   10. A method according to claim 8 or 9, characterized in that a known beam profile and / or wavefront of the laser source is introduced and directed over the cornea and the lower part of the eye within the zone of the pupil opening of the eye.   11. The wavefront profile of the laser beam as reflected by the eye is determined and compared with the profile of the laser beam wavefront to be guided into the eye. Method.   For the purpose of determining the contour shape of the wavefront of the laser beam as it is guided into the eye, the generated laser beam is split so that part is directed directly or indirectly onto the detector. The method according to claim 11, wherein:   13. A method according to any one of claims 8 to 12, characterized in that the refractive power of the eye is determined with local coding by evaluation of the reflected wavefront. Information about the eyes, including the size of the corneal surface, the posterior surface of the cornea, the front surface of the lens, the rear surface of the lens, the surface of the retina, the radius of curvature, the refractive power of the cornea, and the absolute height values are detected. 14. A method according to any one of claims 8 to 13, characterized in that it is determined from the measured data. 15. A method according to any one of claims 8 to 14, wherein information regarding the optical boundary surface of the refractive device of the eye is determined along the optical axis from the pupil opening to the retina.   The laser beam introduced into the eye is focused at the focal point in the eye, the focal point moves along an optical axis extending from the cornea to the retina, and a reflection maximum is obtained along the optical axis. 16. A method according to any one of claims 8 to 15, characterized in that   Method according to claim 16, characterized in that the focal point is moved in a plane perpendicular to the optical axis and the reflection of the laser beam introduced into the eye is measured at various points in this plane.   In the central corneal region with the placido ring projected onto the eye and released from the placido ring, a short coherence measurement system is coaxially connected to the optical axis extending through the pupil and retina of the cornea and the lower section of the eye 18. A method according to any one of claims 8 to 17, characterized in that it is projected in and directed onto it.   The method according to any one of claims 8 to 18, characterized in that the deflection of the laser beam induced in the eye is performed by an x / y scanner so as to obtain a quasi-three-dimensional resolution.

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